Apparatus for finishing gear teeth

ABSTRACT

Apparatus for compressively finishing preformed gear teeth by means of a combination of non-cutting guide and chamfering gears acting on one side of a work gear with an additional non-cutting smoothing or finishing gear acting on the opposite side of the work gear. The guide gear is sandwiched between the chamfering gears and acts with some tooth flank smoothing effect whereas the smoothing or finishing gear achieves the main flank finishing and compressively removes burring of the chamfered tooth corners. The combination solves the problem of the very expensive tool work required when the composite gears must be set with respect to each other so precisely as to eliminate all burring. By eliminating the considerable precision necessary, some burring of the chamfered corners of the work gear is permitted, but this burring is smoothed out by the diametrically opposed finishing gear.

United States Patent [191 Hiirl [451 July 15, 1975 APPARATUS FOR FINISHING GEAR TEETH Adolf Hfirl, Friedrichshafen, Germany [73] Assignee: Zahnradfabrik F riedrichshafen,

Aktiengesellschaft. Friedrichshafen Germany [22] Filed: Mar. 19, 1974 [21] Appl. No.: 452,529

[75] Inventor:

FOREIGN PATENTS OR APPLICATIONS Germany 72/108 Primary Examiner-Lowell A. Larson [57] ABSTRACT Apparatus for compressively finishing preformed gear teeth by means of a combination of non-cutting guide and chamfering gears acting on one side of a work gear with an additional non-cutting smoothing or finishing gear acting on the opposite side of the work gear. The guide gear is sandwiched between the chamfering gears and acts with some tooth flank smoothing effect whereas the smoothing or finishing gear achieves the main flank finishing and compressively removes burring of the chamfered tooth corners. The combination solves the problem of the very expensive too] work required when the composite gears must be set with respect to each other so precisely as to eliminate all burring. By eliminating the considerable precision necessary, some burring of the chamfered corners of the work gear is permitted. but this burring is smoothed out by the diametrically opposed finishing gear.

2 Claims, 1 Drawing Figure APPARATUS FOR FINISHING GEAR TEETH Reference is made to US. Pat. 3,729,967 issued May 1, 1973, owned by the present assignee which shows and claims apparatus for finishing gear teeth of a preformed gear blank by rolling the blank in forced contiguity with a composite gear device comprised of three tool gears sandwiched together in which the outer gears effect chamfering and the central gear effects smoothing of the flanks of the teeth of the work gear.

It has been found, however, that very precise and therefore expensive procedure is necessary in assembling such three tool gears in order that there be no burring occurence. For purposes of economy the present invention eliminates the tooling precision and permits burring of the chamfered work gear corners which burring is then smoothed out by a finishing gear. The arrangement differs in that respect from the patent and also in the respect that the driving rotation of the system is provided for by the finishing gear rather than by the work gear as in the patent. Further differences resides in the fact that while the rotational axis of the finishing gear is fixed the work gear and the composite chamfering and guide gears have mounts which are slideable to effect engagement of the tool gears with work gears. A hydraulic ram is used to motivate the composite tool gear against the work gear which in turn is motivated against the finishing gear.

Referring now to the drawing, details of which have been omitted as not necessary in view of the clear showing in the aforementioned patent for like parts, the apparatus comprises the machine bed 1 having a boss 2 constructed as bearing support for the shaft 3 of a finishing gear 5 supported on a chuck 4 and secured by bolt 6. It will be understood (as shown in the patent) that suitable motor and controls effect rotation of shaft 3 to rotate finishing gear 5.

Carried on bed 1 in ways 7 are freely slideable carriages or mounts 8 and 9. Carriage 8 rotatively supports work gears such as work gear 10 to be finished and chamfered and carriage 9 rotatively supports the composite tool gear device which consist of a guide gear 1 1 sandwiched between chamfering gears 12 and 13. A fixed hydraulic ram 14 on the bed can provide movement of carriage 9 to effect mutual engagement of the several gears as will be clearly understood.

For purposes of balance of forces, gear 5 is diametrically opposite the composite gear device. Preferably an adjustable stop (not shown) is arranged to limit the movement of the hydraulic ram to the exact depth which is desired for the guide gear 11 and the finishing gear 5 to enter between the preformed teeth of a work gear 10. Any conventional limit stop may be used for such purpose and persons skilled in the art, would, of course, be able to devise as a matter or routine a motion limiting device for the ram.

It should be noted that guide gear 11 will have a certain amount of flank smoothin action depending upon the design of the gear, or for purposes of economy it may be designed merely as a guide or drive gear to effect rotative drive of the chamfering gears 12 and 13. The main point is that no precise positioning of the composite gear 11, 12 and 13 is practiced in this invention, whereby a tooling economy is effected, some burring of the chamfered tooth edges of the work gear being thus permitted. However, the finishing gear 5 is provided with teeth which are wider than the teeth of the work gear 10 so that any burring is compressed and polished along with the flanks of the work gear teeth.

Thus the apparatus while requiring an additional component as compared with the patent apparatus effects an economy not only by eliminating precise coaction of the composite tool gears but also by permitting longer periods of operation due to the fact that wear between the composite gears does not cause deterioration of a necessary precision coaction.

It will be obvious from the above that pressure between all gears is provided by the hydraulic ram in conjunction with the slideablility of the carriages for the work gear and the composite gear, initial force being the ram thrust on carriage 9. The engineering of such slideable arrangement is, of course, purely a matter of routine design as is some suitable stop for the ram in order to predetermine a desired thickness of teeth of the work gear.

What is claimed is:

1. An apparatus for chamfering and finishing the teeth of preformed work gears by effecting compression thereof between a chamfering gear device and a finishing gear, comprising in combination:

a support means having a finishing gear on a fixed rotative axis; a chamfering gear device and a first movable mount therefor comprising means for securing said chamfering gear device freely rotative thereon;

a second movable mount disposed intermediate said finishing gear and said first movable mount and having means for supporting a work gear for free rotation thereon;

means for moving said first mount to effect pressure engagement of said chamfering gear device with a work gear on said second mount;

whereby said work gear is forced into engagement with said finishing gear so that rotation of said finishing gear effects rotation of the work gear to transmit the rotation thereof to said chamfering gear device to chamfer the teeth of the work gear whereon any burr resulting is smoothed by said finishing gear.

2. An apparatus as set forth in claim 1, wherein said support comprises a longitudinally extending bed and said mounts comprise carriages slidably carried thereon in alignment with each other; including a hydraulic ram for effecting movement of said first mount on said bed. 

1. An apparatus for chamfering and finishing the teeth of preformed work gears by effecting compression thereof between a chamfering gear device and a finishing gear, comprising in combination: a support means having a finishing gear on a fixed rotative axis; a chamfering gear device and a first movable mount therefor comprising means for securing said chamfering gear device freely rotative thereon; a second movable mount disposed intermediate said finishing gear and said first movable mount and having means for supporting a work gear for free rotation thereon; means for moving said first mount to effect pressure engagement of said chamfering gear device with a work gear on said second mount; whereby said work gear is forced into engagement with said finishing gear so that rotation of said finishing gear effects rotation of the work gear to transmit the rotation thereof to said chamfering gear device to chamfer the teeth of the work gear whereon any burr resulting is smoothed by said finishing gear.
 2. An apparatus as set forth in claim 1, wherein said support comprises a longitudinally extending bed and said mounts comprise carriages slidably carried thereon in alignment with each other; including a hydraulic ram for effecting movement of said first mount on said bed. 